Aphria fell further Thursday morning, down more than 12%, after the company said it had named a committee to review its acquisition of the medical-cannabis company LATAM Holdings, an agreement the short-seller Quintessential Capital Management said was "largely worthless" and benefitted only insiders. After the latest declines, shares had fallen more than 40% since the report was released Monday.

"The Company's Board reiterated its confidence in the process leading to the Acquisition, as well as in its Latin American operations and strategy," an Aphria press release said.

"However, in the face of inaccurate and misleading accusations by certain short-sellers, whose sole interest is in profiting from a decline in the Company's shares, it is undertaking a comprehensive review, led by a Special Committee of independent directors of these, and any other, allegations in the interest of protecting Aphria shareholders."

In a scathing report out Tuesday from Quintessential's Hindenburg Research, the firm called Aphria a "shell game with a cannabis business on the side." It alleged that Aphria's LATAM acquisition allowed insiders to divert as much as $700 million, or nearly half of Aphria's total net assets, through the deal.

"We are committed to protecting our shareholders and restoring market confidence by confirming all the facts through an independent process to rebut innuendo and deception," Aphria CEO Vic Neufeld said in Thursday's press release.

"Until then, it is business as usual at Aphria, as we continue taking significant steps to solidify our position as a premier global cannabis company."